Experimental study on pulsed airflow drying technology in conveying with vibration

A pulsed fluidized bed dryer was designed based on the 5HM-1 model for improving the uniformity of airflow and the smoothness of material conveying. In this new dryer, an inner air distributor was designed and installed to win better pulsofluidizing effects, a guiding part with bigger diameter in sequence was introduced to obtain better uniformity of airflow, a vibrating conveyer was installed to convey material smoothly, and a material conducting unit was added to overcome the "reverse flow" . Corn and beer lees drying experiments were conducted on the dryer at air temperature ranging from 70℃ to 75℃ and 65℃ to 70℃, respectively. The best drying results for the two materials were obtained at the airflow pulsed frequencies of 3 Hz and 2 Hz, with the bed inclined angles from 2.5° to 3.8°and 3.8° to 4.8° at the airflow rates ranging from 0.8 m/s to 1.0 m/s and 0.9 m/s to 1.1 m/s, respectively. The optimal vibrating frequency for the two materials was 32 Hz under the selected bed inclined angles and airflow rates. For the two materials used in the experiments, the drying strengths were 20.87 kg(H₂O)/(m²·h) and 21.76 kg(H₂O)/(m²·h), the heat consumptions were 5.86 MJ/kg(H₂O) and 4.91 MJ/kg(H₂O) and the energy consumptions were 7.38 MJ/kg(H₂O) and 6.47 MJ/kg(H₂O), respectively.